The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 1995
Filed:
Apr. 07, 1992
Michael R Keeling, Cambridge, GB;
Hillar Weinberg, Cambridge, GB;
Abstract
An ink jet printer automatically adjusts the amplitude of the modulation signal applied to a transducer (159) to break the ink jet into droplets. Correct modulation amplitude is determined from changes in jet break-up length, as determined by changes in jet break-up length, as determined by changes in jet break-up phase relative to the modulation signal. The printer has interchangeable print heads (3), which may have different nozzle sizes. A calibration code, specifying the particular values of ink pressure, jet velocity and charge correction required for optimum performance of a particular print head (3), may be entered into control logic (93), which operates the printer accordingly. Most print head components are mounted on a mounting subtract (111), with all connections being made to the underside of the mounting subtract (111) and sealed with a potting compound, to avoid damage. Ink viscosity is controlled in response to ink pressure, which is in turn controlled in response to ink jet velocity. Thus all three parameters are maintained without the need for a viscosity meter. Ink jet velocity is sensed from signals induced by charged drops on spaced apart sensors (89, 91), the outputs from which are wired together and fed to a common comparator (105), which simplifies construction.